Anode composition containing an anionic binder

Abstract

The present invention relates to an aqueous anode composition comprising metal particles or fibers or carbon graphite particles or fibers and a binder comprising at least one water-soluble polymer P prepared based on (meth)acrylic acid and (meth)acrylate. The present invention also relates to a method for manufacturing an anode using the aqueous composition.

Description

Technical Field

[0001] The present invention relates to an aqueous anode composition comprising metal or carbon graphite particles or fibers and a binder comprising at least one water-soluble anionic copolymer P made from (meth)acrylic acid and (meth)acrylate. The present invention also relates to a method for manufacturing an anode using the aqueous composition.

Background Art

[0002] Anode compositions generally containing carbon or metal in particulate form associated with a binding composition are known. This binding composition must be able to effectively bind carbon or metal to a substrate to form an anode. The most common binding composition contains a styrene-butadiene polymer. The composition enables the fixation of the particles to the metal substrate. Therefore, the binding properties are critical when manufacturing anodes using these anode compositions. In addition, mechanical strength or electrochemical resistance is particularly required.

[0003] An easy and uniform application of the anode composition is necessary to obtain a uniform layer, limit or avoid defects on the anode surface, and result in a uniform and particularly effective conductive layer.

[0004] Generally, the binding composition also contains various additives such as thickeners, dispersants, for example cellulose derivatives. The most common cellulose derivatives are carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose.

[0005] These anode compositions often contain silicon to increase the capacity of the fabricated anode. During the charge-discharge cycles of a battery containing these anodes, it is common to observe strains that can cause irreversible changes in the anode, particularly as a result of the increased volume of silicon. Therefore, resistance to strain is also a desirable property.

[0006] The number of components used when preparing the anode composition should be able to be reduced.

[0007] The compatibility of the different components of the anode composition is also an important factor when preparing the anode composition and when using these compositions to prepare anodes.

[0008] Document EP2680349 relates to the preparation of a secondary battery anode using a polyacrylic binder. Document EP2592679 describes a binder for a secondary battery electrode containing water-insoluble copolymer particles having an average diameter in the range of 0.3 μm to 0.7 μm. Document EP3001487 discloses a water-insoluble core-shell binder for a secondary battery electrode in which the core contains styrene-butadiene rubber and the shell contains a poly(styrene-acrylate) copolymer.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] Conventional anode compositions are not always satisfactory. Therefore, there is a need for an anode composition that provides a solution to all or part of the problems of conventional anode compositions.

Means for Solving the Problems

[0011] Therefore, the present invention is an aqueous anode composition T, ·The weight average molecular weight Mw (measured by SEC) is in the range of 2,000 g / mol to 1,000,000 g / mol and is in the presence of at least one initiator compound. a. At least one anionic monomer (a) selected from acrylic acid, acrylate, methacrylic acid, methacrylate, and combinations thereof, which is 20 to 95% by weight based on the total weight of monomers (a) and (b). b. At least one water-soluble polymer P produced by the polymerization reaction of at least one C1-C8 ester (b) of a compound derived from an acid selected from acrylic acid, methacrylic acid, maleic acid, itaconic acid, and crotonic acid, which is 5 to 80% by weight based on the total weight of monomers (a) and (b). At least one binder L, which is 0.5% to 15% by dry weight based on the total amount by dry weight of the binder L and the material E. ·At least one material E selected from metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, silicon particles, and combinations thereof, which is 85% to 99.5% by dry weight based on the total weight by dry weight of the binder L and the material E. A composition T is provided.

[0012] Essentially, in the present invention, the polymer P is produced using monomers a and b.

[0013] Preferably, according to the present invention, the anionic monomer (a) can be selected from acrylic acid, methacrylic acid, and combinations thereof. Preferably, the anionic monomer (a) is acrylic acid. Also, preferably, according to the present invention, the monomer (a) can be combined with at least one other anionic monomer selected from acrylic acid, methacrylic acid, acrylate, methacrylate, maleic acid, maleate, itaconic acid, itaconate, crotonic acid, crotonate, acrylic acid oligomer, and combinations thereof, which is different from the monomer (a).

[0014] Preferably, according to the present invention, the ester (b) is a C1-C7 ester or a C1-C6 ester or a C1-C4 ester, preferably a C1-C3 ester. More preferably, according to the present invention, the ester (b) is an acrylate ester or a methacrylate ester, preferably an acrylate ester.

[0015] Also preferably, according to the present invention, the ester (b) is selected from methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, ethylhexyl methacrylate, and combinations thereof. More preferentially, the ester (b) is selected from ethyl acrylate, methyl acrylate, butyl acrylate, methyl methacrylate, and combinations thereof.

[0016] Generally, the ester (b) is not an alicyclic C1-C8 ester.

[0017] Advantageously, according to the present invention, a single polymerization reaction is carried out.

[0018] Preferably, according to the present invention, the polymerization reaction can also use at least one crosslinking monomer (c) or at least one monomer (c) containing at least two olefinic unsaturations. More preferably, the monomer (c) is a polyvinyl aromatic monomer (e.g., divinylbenzene and diallyl phthalate); a polyalkenyl ether (e.g., triallyl pentaerythritol, diallyl pentaerythritol, diallyl sucrose, octaallyl sucrose, trimethylolpropane diallyl ether); a polyvalent unsaturated ester of a polyhydric alcohol or a polyvalent unsaturated ester of a polyvalent acid (e.g., trimethylolpropane tri(meth)acrylate, trimethylolpropane, polyethylene glycol di(meth)acrylate); a diacrylate ester, particularly a dimethacrylate ester derived from a polyol selected from pentaerythritol, sorbitol, sucrose; divinylnaphthalene, trivinylbenzene, 1,2,4-trivinylcyclohexane, triallyl pentaerythritol, diallyl pentaerythritol, diallyl sucrose, trimethylolpropane diallyl ether, 1,6-hexanediol di(meth)acrylate, allyl (meth)acrylate, diallyl itaconate, diallyl fumarate, diallyl maleate, butanediol dimethacrylate, ethylene di(meth)acrylate, poly(ethylene glycol) di(meth)acrylate, trimethylolpropane tri(meth)acrylate, methylene bis(meth)acrylamide, triallyl cyanurate, diallyl phthalate, divinylbenzene; diallyl phthalate (DAP); ethylene glycol dimethacrylate (EGDMA); methylene bisacrylamide (MBA); divinylbenzene (DVB); bicyclopentenyl oxyethyl methacrylate (FRA); trimethylolpropane triallyl ether (APE) and combinations thereof. More preferentially, according to the present invention, the monomer (c) can be selected from diallyl phthalate (DAP), ethylene glycol dimethacrylate (EGDMA), trimethylolpropane diacrylate, trimethylolpropane dimethacrylate and combinations thereof.

[0019] Preferably, monomer (c) can be used in an amount of less than 5% by weight, preferably 0.01 to 4% by weight, particularly 0.02 to 4% by weight, or 0.02 to 2% by weight, particularly 0.02 to 1% by weight, based on the total weight of the monomers.

[0020] Also, preferably, according to the present invention, at least one hydrophobic monomer (d) different from compound (c) can be used in the polymerization reaction. Preferably, monomer (d) is a compound of formula (I): R 1 -(EO) m -(PO) p -R 2 (I)(I) In the formula, -m and p are the same or different and independently represent an integer or a decimal number of 0 or less than 150, and m or p is different from 0, -EO independently represents a CH2CH2O group, -PO independently represents a group selected from CH(CH3)CH2O and CH2CH(CH3)O, -R 1 independently represents a group containing at least one polymerizable olefin unsaturation, preferably an acrylate group or a methacrylate group, -R 2 independently represents a linear or branched C6-C 40 alkyl group, a phenyl group, a polyphenyl group, preferably a linear or branched C 10 -C 30 alkyl group, more preferably a linear or branched C 12 -C 22 alkyl group, or 2 to 5 phenyl or tristyrylphenyl groups or pentastyrylcumylphenyl groups. Also, preferably, less than 20% by weight, preferably 0.05 to 20% by weight, particularly 0.1 to 10% by weight of monomer (d) can be used based on the total weight of the monomers.

[0021] Also, preferably, according to the present invention, at least one compound (e) selected from hydroxyethyl acrylate phosphate, hydroxypropyl acrylate phosphate, hydroxyethylhexyl acrylate phosphate, phosphorylated hydroxyethyl methacrylate, phosphorylated hydroxypropyl methacrylate, phosphorylated hydroxyethylhexyl methacrylate, salts thereof, and combinations thereof can be used in the polymerization reaction.

[0022] Also, preferably, less than 20% by weight, preferably 0.2 to 20% by weight, particularly 0.5 to 10% by weight of monomer (e) can be used based on the total weight of the monomers.

[0023] Also, preferably, according to the present invention, at least one compound (f) selected from hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethylhexyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxyethylhexyl methacrylate can be used in the polymerization reaction.

[0024] Also, preferably, less than 20% by weight, preferably 0.2 to 20% by weight, particularly 0.5 to 10% by weight of monomer (f) can be used based on the total weight of the monomers.

[0025] Also, preferably, according to the present invention, the polymer P is prepared using a combination of monomers a and b, a combination of monomers a, b, and c, a combination of monomers a, b, and d, a combination of monomers a, b, and e, a combination of monomers a, b, and f, a combination of monomers a, b, c, and d, a combination of monomers a, b, c, and e, a combination of monomers a, b, c, and f, a combination of monomers a, b, c, d, and e, a combination of monomers a, b, c, d, and f, a combination of monomers a, b, d, and e, a combination of monomers a, b, d, and f, a combination of monomers a, b, e, and f, a combination of monomers a, b, c, d, e, and f. More preferably, according to the present invention, the polymer P is prepared using only a combination of monomers a and b.

[0026] Therefore, when preparing the polymer P of the present invention, monomers a and b are essential. Therefore, monomers c, d, e, and f can be optionally used. When monomers c, d, e, and f are absent, the polymer P is prepared from only monomers a and b.

[0027] Furthermore, the polymer P can be prepared without specific monomers. In particular, the polymer P is prepared in the absence of organic sulfur monomers such as sulfonated monomers or sulfated monomers. In this case, the specific organic sulfur monomers not used are selected from 2-acrylamido-2-methylpropanesulfonic acid (AMPS), allylsulfonic acid, alkylene sulfonates, alkylene aryl sulfonates, especially styrene sulfonate, vinyl sulfonate, methallyl sulfonate, allylsulfonic acid, methallyl sulfate, allyl sulfate, 2-sulfoethyl methacrylate, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 3-sulfopropyl methacrylate, salts thereof, and combinations thereof.

[0028] Other monomers, especially (meth)acrylamide monomers, (acryl)nitrile monomers, fluorinated monomers, acetate monomers, and imide monomers can be excluded from the preparation of polymer P. Preferably, according to the present invention, polymer P is prepared in the absence of halogenated monomers, especially in the absence of fluorinated monomers.

[0029] When preparing polymer P, the ratio of monomers a and b can vary considerably. Preferably, according to the present invention, the polymerization reaction is by weight, relative to the total weight of monomers (a) and (b), - 30 to 70% by weight of monomer (a), preferably 35 to 70% by weight, or - 30 to 70% by weight of monomer (b), preferably 30 to 65% by weight is used.

[0030] According to the present invention, copolymer P is water-soluble. Preferably, according to the present invention, the water-soluble copolymer P is prepared using a majority amount of anionic monomers by weight. Advantageously, polymer P is soluble in any amount of water at room temperature, preferably at different pH values, especially in the pH range of 2 to 12.

[0031] Preferably, according to the present invention, the pH of polymer P is less than 12 or less than 11, or in the range of 2 to 12, or 5 to 11. Also, preferably, according to the present invention, the pKa of polymer P is less than 5 or in the range of 1.5 to 5.

[0032] Preferably, according to the present invention, the polymerization reaction is carried out at a temperature above 30 °C and below 130 °C, preferably below 100 °C, or below 90 °C, or below 80 °C, or below 75 °C. Preferably, during the polymerization reaction for producing the polymer P, the initiator compound is selected from peroxides (e.g., hydrogen peroxide), hydroperoxides (e.g., tert-butyl hydroperoxide), persulfates (e.g., sodium persulfate, ammonium persulfate, potassium persulfate), combinations thereof, and compounds thereof with metal salts, preferably iron salts (e.g., Fe(II) or Fe(III)), copper salts (e.g., Cu(I) or Cu(II)), and metal salts selected from combinations thereof.

[0033] Preferably, according to the present invention, the polymer P is produced in a solvent selected from polar solvents, particularly water, alcohol, toluene, ketone, chlorinated solvents, esters, and combinations thereof.

[0034] Also, preferably, according to the present invention, the polymer P can be produced in the presence of a chain transfer agent, preferably in the presence of a compound selected from isopropyl alcohol, mercaptan, dodecyl-mercaptan, phosphorous acid, phosphite, hypophosphorous acid, hypophosphite, bisulfite, alkyl iodide, alkyl bromide, and combinations thereof.

[0035] According to the present invention, the polymer P may not be neutralized, or it may be partially neutralized, or it may be completely neutralized. Preferably, the polymer P is not neutralized or is partially neutralized. According to the present invention, the carboxyl groups of the polymer P can be partially neutralized at a ratio of 70 to 97 mol%, preferably 90 to 95 mol%. The polymer P can be partially or completely neutralized using at least one monovalent ion or at least one divalent ion. According to the present invention, the polymer P can be partially or completely neutralized using a combination of at least one monovalent ion and at least one divalent ion. Thus, according to the present invention, the polymer P can be completely or partially neutralized with variable relative molar ratios of monovalent and divalent ions. Preferably, according to the present invention, the molar ratio of monovalent ions / divalent ions is composed of 90 / 10 to 10 / 90, or 80 / 20 to 20 / 80, preferably 80 / 20 to 60 / 40, for example 70 / 30 or 50 / 50.

[0036] According to the present invention, the neutralization can be carried out using a monovalent ion selected from primary amines, secondary amines, or K + , Na + , Li + , NH4 + , or amines and combinations thereof. Preferred monovalent ions are selected from Na + and Li + . Nevertheless, the polymer P according to the present invention can be neutralized in the absence of Li + ions. According to the present invention, the neutralization can also be carried out using a divalent ion selected from Ca 2+ , Zn 2+ , Mg 2+ and combinations thereof. A preferred divalent ion is Ca 2+ .

[0037] According to the present invention, the polymer P can be neutralized using at least one compound selected from NaOH, KOH, LiOH, ammonium derivatives, ammonia, ammonium hydroxide, primary amines, secondary amines, CaO, Ca(OH)2, ZnO, Zn(OH)2, MgO, Mg(OH)2, and combinations thereof. Neutralizing the polymer P using ammonia is particularly advantageous when using the composition T at a pH of less than 7, preferably less than 5. According to the present invention, the polymer P can be completely or partially neutralized using a base selected from amine bases such as ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, α,α'-diaminoxylene, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, triethanolamine, aminomethylpropanol, or 2-amino-2-methylpropanol (AMP) and combinations thereof.

[0038] Preferably, the polymer P has a weight average molecular weight Mw (measured by SEC) of less than 900,000 g / mol, less than 800,000 g / mol, less than 500,000 g / mol, more preferably less than 350,000 g / mol. The polymer P generally has a weight average molecular weight Mw (measured by SEC) greater than 5,000 g / mol, preferably greater than 20,000 g / mol.

[0039] The polymer P generally has a polydispersity index PI (measured by SEC) in the range of less than 4, or 1.2 to 4, or 1.5 to 4, 1.2 to 3, or 1.5 to 3, 1.2 to 2.5, and more preferably 1.5 to 2.5.

[0040] According to the present invention, the molecular weight or mass of polymer P is determined by size exclusion chromatography (SEC). A test portion of the polymer solution corresponding to 90 mg of dry solids is placed in a 10 mL flask. The mobile phase is added together with 0.04% dimethylformamide (DMF) until the total mass reaches 10 g. The composition of this mobile phase is as follows: NaHCO3: 0.05 mol / L, NaNO3: 0.1 mol / L, triethanolamine: 0.02 mol / L, NaN3: 0.03% by mass. The SEC chain consists of a Waters 510 isocratic pump with a flow rate set at 0.8 mL / min, a Waters 717+ sample changer, an oven containing a Waters Ultrahydrogel Column Guard precolumn with a length of 6 cm and an inner diameter of 40 mm, followed by a Waters Ultrahydrogel linear column with a length of 30 cm and an inner diameter of 7.8 mm. Detection is provided by a Waters 410 RI differential refractometer. The oven is set at a temperature of 60 °C and the refractometer is set at a temperature of 45 °C. The SEC instrument is calibrated with a series of sodium polyacrylate standards supplied by Polymer Standards Service, and the molecular weight at the peak apex is composed of 1,000 g / mol to 1.10 6 g / mol, and the polydispersity index is calibrated with 1.4 to 1.7. The calibration curve is linear, taking into account the correction obtained using the flow marker: dimethylformamide (DMF). The acquisition and processing of the chromatogram are performed using "PSS WinGPC Scientific" software v 4.02. The obtained chromatogram is incorporated into the region corresponding to molecular weights exceeding 250 g / mol.

[0041] Generally, according to the present invention, binder L contains polymer P in the form of particles.

[0042] Preferably, according to the present invention, binder L contains 5 wt% to 100 wt%, preferably 10 wt% to 70 wt% of polymer P.

[0043] Essentially, according to the present invention, the aqueous composition T contains at least one binder L. Advantageously, the composition T according to the present invention may not contain other binders. Also advantageously, the composition T according to the present invention also contains at least one other binder different from the agent L, preferably an other binder selected from (meth)acrylic polymers, comb polymers, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, alginates, styrene-butadiene polymers, poly(allylamine, HCl), amylopectin, and combinations thereof, or polyethylene, fluorinated binding compounds such as polyvinylidene fluoride (PVDF), poly(vinylpyrrolidone), polytetrafluoroethylene (PTFE), ethylene chlorotrifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), fluoroacrylate, fluorosilicone, and combinations thereof.

[0044] Also advantageously, the composition T according to the present invention can also contain at least one organic acid or at least one inorganic acid, preferably an acid selected from sulfuric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, and combinations thereof.

[0045] Essentially, according to the present invention, the aqueous composition T contains at least one material E. Preferably, according to the present invention, the composition T contains a material E optionally doped with at least one element selected from silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, preferably selected from lithium, germanium, silicon, and combinations thereof. Preferred materials E are selected from carbon graphite, silicon, and combinations thereof.

[0046] In particular, Material E can be selected from conductive carbon compounds, furnace black, acetylene black, ketjen black, carbon nanotubes (CNT), synthetic graphite, natural graphite, hard carbon, activated carbon, carbon black, graphene, mesoporous carbon, amorphous silicon, semi-crystalline silicon, silicon oxide, silicon nanowires, tin, tin oxide, germanium, lithium titanate, materials suitable for use as anodes in lithium-ion batteries, and combinations thereof.

[0047] According to the present invention, Material E can be a conductive material or can include a material that can intercalate or accept lithium ions.

[0048] Advantageously, according to the present invention, Composition T may also contain other components. In particular, Composition T according to the present invention may also contain compounds selected from polyethylene, fluorinated bonding compounds such as polyvinylidene fluoride (PVDF), poly(vinyl-pyrrolidone), polytetrafluoroethylene (PTFE), chlorotrifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), fluoroacrylate, fluorosilicone, and combinations thereof.

[0049] Among Composition T, the proportions of the various components can vary. Preferably, Composition T according to the present invention, based on the total weight by dry weight of the binder and Material E, · a binder in a dry weight of 0.5% to 15%, particularly binder L, and · Material E in a dry weight of 85% to 99.5% is included.

[0050] The present invention also provides a method for producing aqueous Composition T. The production method is - the production of binder L according to the present invention, - Addition of at least one material E selected from among metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, and combinations thereof, preferably, the material E is selected from among silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, and optionally, preferably doped with at least one element selected from among lithium, germanium, and combinations thereof.

[0051] The present invention also provides a method for manufacturing an anode using the composition T according to the present invention. The anode manufacturing method comprises - Applying at least one composition T according to the present invention to a substrate; - Drying the coated substrate and then calendaring it.

[0052] Advantageously, according to the present invention, the substrate or current collector can be in the form of a plate, film, mesh, foam, sheet, rod, or any other morphological structure that does not significantly impair its ability to collect current. Generally, the substrate is in the form of a sheet, preferably a sheet of copper metal (Cu 0 ) or a sheet of nickel metal (Ni 0 ).

[0053] Preferably, the present invention provides a production method according to the present invention, wherein the application is carried out at a pH of less than 7, or in the pH range of 4 to 6.5. Further preferably, the present invention provides a production method according to the present invention, wherein the application of the composition T to the substrate is carried out on the metal surface up to a thickness after drying and calendaring of less than 500 μm, preferably less than 100 μm, or less than 50 μm. Generally, according to the present invention, the thickness of the composition T after application, drying and calendaring to the substrate exceeds 5 μm. According to the present invention, the thickness of the composition T after application, drying and calendaring to the substrate is measured using a coating thickness gauge of 1 μm to 1,000 μm, particularly 20 μm to 30 μm. Particularly preferably, the present invention provides a production method in which the application of the composition T to the substrate is uniform. According to the present invention, the composition is applied uniformly when the particles of material E are uniformly distributed in the layer. According to the present invention, the uniformity is measured by visual inspection by direct visual observation with the naked eye. According to the present invention, the application is uniform if no aggregates are visible on the surface of the layer when viewed from the front in daylight.

[0054] Preferably, when manufacturing the anode according to the present invention, at least one of the application steps is carried out at a pH of less than 7, preferably less than 5.

[0055] The composition T according to the present invention is applied by methods known per se. This can be applied by spraying, rolling, coating, heliogravure, or any other means of applying an aqueous formulation to the surface.

[0056] The present invention enables the production of an anode using the composition T according to the present invention. Thus, the present invention provides an anode produced according to the production method according to the present invention.

[0057] According to the present invention, the specific, advantageous, or preferred features of the composition T according to the present invention similarly clarify the specific, advantageous, or preferred production method, manufacturing method, and anode according to the present invention.

Embodiments for Carrying Out the Invention

[0058] The following examples illustrate various aspects of the present invention.

Example

[0059] [Preparation and Property Evaluation of Binder L Containing Polymer P1 According to the Present Invention] 90 g of acrylic acid (monomer a), 10 g of ethyl acrylate (monomer b), and 830 g of deionized water are introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 70 °C. Then, a solution containing 0.50 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. Again, a solution containing 0.20 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. After cooling to room temperature, the pH is adjusted to 2.5 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, a water-soluble binder L according to the present invention containing a copolymer P1 having a weight average molecular weight Mw of 165,000 g / mol as measured by SEC in an aqueous solution with a concentration of 11.2 wt% is obtained.

[0060] [Preparation and Property Evaluation of Binder L Containing Polymer P2 According to the Present Invention] 90 g of acrylic acid (monomer a), 10 g of ethyl acrylate (monomer b), and 820 g of deionized water are introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 70 °C. Then, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. Again, a solution containing 0.35 g of ammonium persulfate is poured all at once into 20 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. After cooling to room temperature, the pH is adjusted to 5.7 by adding 39.4 g of LiOH·H2O to 40 g of deionized water.

[0061] Thereby, a water-soluble binder L according to the present invention containing a copolymer P2 having a weight average molecular weight Mw of 256,000,000 g / mol as measured by SEC in an aqueous solution with a concentration of 10.4 wt% is obtained.

[0062] [Preparation of Aqueous Anode Composition T according to the Present Invention] An aqueous composition containing 5% by dry weight of polymer P1 and 5% by dry weight of carbon black (Black C65 "Imerys") is prepared with binder L (11.2% by weight) containing polymer P1 while stirring at 3,000 rpm for 2 hours using a stirrer equipped with a 40 mm disk wheel.

[0063] Then, this aqueous composition of 0.32 g of carbon black and polymer P1, 1.2 g of silicon particles (SI-100, 30 - 50 nm, "Get Nano Materials") and deionized water are introduced into a glass beaker while stirring at 4,500 rpm for 1 hour using a stirrer equipped with a 25 mm disk wheel. A mixture of 6.32 g of graphite (92.5% by weight of GHDR, 5% by weight of SFG15L, 2.5% by weight of KS6L, "Imerys") and deionized water is added. Stirring is continued for 1 hour. Then, 0.4 g of styrene-butadiene bound latex (SNR BM-451B "Zeon" latex, 40% by weight) is added and stirred at 500 rpm for 30 minutes. The amount of water added is specified to obtain aqueous anode composition T1 according to the present invention having a final concentration of 44.6% by dry weight.

[0064] Similarly, aqueous anode composition T2 according to the present invention having a final concentration of 44.6% by dry weight is prepared. This contains binder L according to the present invention containing copolymer P2 (10.4% by weight).

[0065] [Manufacture and Property Evaluation of Anode according to the Present Invention] A copper plate with a thickness of 100 μm is coated with a layer of composition T1 according to the present invention with a thickness of 20 μm using a manual application bar. A disk with a diameter of 15 mm is cut out using a precision cutter. The coated disk is calendered at 0.6 t / cm 2 using a press. Then, the disk is dried in an oven and the temperature is gradually raised to 110 °C over 18 hours under vacuum.

[0066] After cooling to room temperature, the uniformity of the layer is evaluated by visual inspection. No aggregates or surface irregularities are visible on the surface of the layer when viewed from the front in daylight.

[0067] Next, the density of the obtained anode is measured by weighing it with a balance, and then its porosity is calculated.

[0068] Anodes are similarly fabricated and characterized using the aqueous anode composition T2. The results are shown in Table 1.

[0069] [Table 1]

[0070] Thus, the aqueous anode composition containing the binder according to the present invention enables the production of an anode that is stable and in which the active material binds well to the copper layer. The anode composition according to the present invention enables the production of an anode having a uniform layer. Therefore, these anodes can be easily used for manufacturing rechargeable cells or secondary batteries.

[0071] [Manufacture and Characterization of Half-Cells Containing Anodes According to the Present Invention] In a glove box ("MBraun LabStar") maintained in an inert atmosphere (Ar, O2 and H2O < 0.5 ppm), an electrolyte ("Solvionic" 1M, LiPF6 in a mixture of ethylene carbonate - ethyl methyl carbonate containing 2% vinyl carbonate and 10% fluoroethylene carbonate), an anode according to the present invention, a pre-cut lithium disk (diameter 15.6 mm and thickness 0.25 mm), then a separator disk ("Whatman" GF / C 1822 - 849, diameter 17 mm, thickness 0.26 mm and pore size 1.2 μm) and a separator disk ("Celgard" 2325 three-layer PE / PP / PE) are assembled onto the working electrode.

[0072] The half-cell containing the anode according to the present invention produced by the aqueous anode composition T2a is subjected to charge-discharge cycles in a chamber with a thermostat at 25°C as follows.

[0073] - 2 cycles: Discharge to 0.005 V at C / 7 with a C / 100 cut-off, then charge at C / 7 with a 1.0 V cut-off. - 3 cycles: Discharge to 0.005 V at C / 5 with a C / 50 cut-off, then charge at C / 5 with a 1.0 V cut-off. - 102 cycles: Discharge to 0.005 V at 1C with a C / 40 cut-off, then charge at 1C with a 1.0 V cut-off.

[0074] The half-cell containing the anode according to the present invention is similarly produced and characterized by the aqueous anode composition T2. For each half-cell, the charge (load), capacity, initial Coulombic efficiency (ICE), Coulombic efficiency after 10 cycles and then after 20 cycles (CE10, CE20), Coulombic cycle efficiency - CCE1, and capacity retention rate with respect to the first cycle after 10 cycles and then after 20 cycles (CR10, CR20) are determined. The results are shown in Table 2.

[0075] [Table 2]

[0076] The binder according to the present invention is very effective for obtaining anodes and cells with a high silicon concentration and enables the production of an aqueous anode composition that particularly arouses interest in electrochemical properties.

Claims

1. An aqueous anode composition T, comprising: - at least one water-soluble polymer P produced by a polymerization reaction of monomers (a) and (b), having a weight average molecular weight Mw measured by SEC in the range of 2,000 g / mol to 1,000,000 g / mol, in the presence of at least one initiator compound; a. at least one anionic monomer (a) selected from acrylic acid, acrylate, methacrylic acid, methacrylate, and combinations thereof, in an amount of 20 to 95% by weight based on the total weight of monomers (a) and (b); b. At least one C of a compound derived from an acid selected from acrylic acid, methacrylic acid, maleic acid, itaconic acid, and crotonic acid, in an amount of 5 to 80% by weight based on the total weight of monomers (a) and (b) １ -C ８ ester (b) at least one binder L in an amount of 0.5% to 15% by dry weight, based on the total amount by dry weight of the binder L and the material E, and - at least one material E selected from metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, silicon particles, and combinations thereof, in an amount of 85% to 99.5% by dry weight, based on the total amount by dry weight of the binder L and the material E. Composition T.

2. - The anionic monomer (a) is selected from acrylic acid, methacrylic acid, and combinations thereof, preferably the anionic monomer (a) is acrylic acid, or - The monomer (a) is combined with at least one other anionic monomer different from the monomer (a), and is selected from acrylic acid, methacrylic acid, acrylate, methacrylate, maleic acid, maleate, itaconic acid, itaconate, crotonic acid, crotonate, acrylic acid oligomers, and combinations thereof. The composition T according to claim 1.

3. - Ester (b) is an alicyclic C １ - C ８ ester that is not, or ester (b) is a C １ - C ７ ester, or a C １ - C ６ ester, or a C １ - C ４ ester, preferably a C １ - C ３ ester, or - The ester (b) is an acrylic acid ester or a methacrylic acid ester, preferably an acrylic acid ester, or - The ester (b) is selected from methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, ethylhexyl methacrylate, and combinations thereof. More preferably, the ester (b) is selected from ethyl acrylate, methyl acrylate, butyl acrylate, methyl methacrylate, and combinations thereof. The composition T according to claim 1 or 2.

4. A single polymerization reaction is carried out, or the polymerization reaction is also... · At least one crosslinkable monomer (c) or at least one monomer (c) containing at least two olefinic unsaturations, preferably less than 5% by weight, preferably 0.01 - 4% by weight, particularly 0.02 - 4% by weight or 0.02 - 2% by weight, particularly 0.02 - 1% by weight of monomer (c) based on the total weight of the monomers, or · At least one hydrophobic monomer (d) selected preferably from compounds of formula (I), different from compound (c): R １ -(EO) ｍ -(PO) ｐ -R ２ (I) In the formula,[[]] - m and p are the same or different and independently represent an integer or a decimal number of 0 or less than 150, and m or p is different from 0, -EO independently represents CH ２ CH ２ represents an O group, -PO is independently, CH(CH ３ )CH ２ O and CH ２ CH(CH ３ )O, and represents a group selected from among them, -R １ independently represents at least one group containing a polymerizable olefin unsaturation, preferably an acrylate group or a methacrylate group, -R ２ is, independently, a linear or branched C ６ -C ４０ alkyl group, phenyl group, polyphenyl group, preferably a linear or branched C １０ -C ３０ alkyl group, more preferably a linear or branched C １２ -C ２２ alkyl group, or a group containing 2 to 5 phenyl or tristyrylphenyl or pentastyrylcumylphenyl groups, preferably less than 20% by weight, preferably 0.05 - 20% by weight, particularly 0.1 - 10% by weight of monomer (d) based on the total weight of the monomers, or · At least one compound (e) selected from phosphorylated hydroxyethyl acrylate, phosphorylated hydroxypropyl acrylate, phosphorylated hydroxyethyl hexyl acrylate, phosphorylated hydroxyethyl methacrylate, phosphorylated hydroxypropyl - methacrylate, phosphorylated hydroxyethyl hexyl methacrylate, salts thereof and combinations thereof, preferably less than 20% by weight, preferably 0.2 - 20% by weight, particularly 0.5 - 10% by weight of monomer (e) based on the total weight of the monomers, or · At least one compound (f) selected from hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl hexyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl hexyl methacrylate, preferably less than 20% by weight, preferably 0.2 - 20% by weight, particularly 0.5 - 10% by weight of monomer (f) based on the total weight of the monomers, is used, the composition T according to one of claims 1 - 3.

5. · The polymer P is prepared in the presence of at least one initiator compound selected from peroxides (e.g., hydrogen peroxide), hydroperoxides (e.g., tert - butyl hydroperoxide), persulfates (e.g., sodium persulfate, ammonium persulfate, potassium persulfate), combinations thereof and adducts thereof with metal salts, preferably iron salts (e.g., Fe(II) or Fe(III)), copper salts (e.g., Cu(I) or Cu(II)) and combinations thereof, or - Polymer P is prepared in the presence of a chain transfer agent, preferably in the presence of a compound selected from isopropyl alcohol, mercaptan, dodecyl mercaptan, phosphorous acid, phosphate, hypophosphorous acid, hypophosphite, bisulfite, alkyl iodide, alkyl bromide, and combinations thereof, or - The pH of polymer P is less than 12 or less than 11, or in the range of 2 to 12 or 5 to 11, or - The pKa of polymer P is less than 5, or in the range of 1.5 to 5, or - Polymer P is not neutralized, or polymer P is preferably completely or partially neutralized using at least one compound selected from LiOH, NaOH, KOH, ammonium derivatives, ammonia, ammonium hydroxide, amino bases such as triethanolamine, aminomethyl-propanol or 2-amino-2-methyl-propanol (AMP), CaO, Ca(OH) ２ , ZnO, Zn(OH) ２ , MgO, Mg(OH) ２ and the composition T according to one of claims 1 to 4, which is completely or partially neutralized using at least one compound selected from these combinations.

6. The polymerization reaction is carried out with respect to the total weight of monomers (a) and (b) - 30 to 70% by weight, preferably 35 to 70% by weight, of monomer (a) or - 30 to 70% by weight, preferably 30 to 65% by weight, of monomer (b), is used in the composition T according to any one of claims 1 to 5.

7. - Polymer P has a weight average molecular weight Mw of less than 900,000 g / mol, less than 800,000 g / mol, more preferably less than 500,000 g / mol or less than 350,000 g / mol as measured by SEC, or - Polymer P has a weight average molecular weight Mw of greater than 5,000 g / mol, preferably greater than 20,000 g / mol as measured by SEC, in the composition T according to any one of claims 1 to 6.

8. Contains at least one binder L and does not contain other binders, or - At least one other binder different from the agent L, preferably another binder selected from (meth)acrylic polymers, comb polymers, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, alginate, styrene-butadiene polymers, poly(allylamine, HCl), amylopectin, and combinations thereof, or another binder further containing a compound selected from polyethylene, fluorinated binding compounds such as polyvinylidene fluoride (PVDF), poly(vinyl pyrrolidone), polytetrafluoroethylene (PTFE), ethylene chlorotrifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), fluoroacrylate, fluorosilicone, and combinations thereof. Composition T according to any one of claims 1 to 7, further comprising at least one organic acid or at least one inorganic acid, preferably an acid selected from sulfuric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, and combinations thereof.

9. Material E is selected from silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, and optionally, preferably doped with at least one element selected from lithium, germanium, silicon, and combinations thereof. Composition T according to any one of claims 1 to 8.

10. Based on the total amount by dry weight of the binder and Material E, ・ A binder in an amount of 0.5% to 15% by dry weight, particularly binder L, and ・ Material E in an amount of 85% to 99.5% by dry weight Composition T according to claim 9.

11. - Preparation of binder L according to any one of claims 1 to 8, - Addition of at least one Material E selected from metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, and combinations thereof, preferably, Material E is selected from silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, and optionally, preferably doped with at least one element selected from lithium, germanium, and combinations thereof. The addition. A method for preparing the aqueous composition T according to any one of claims 1 to 10.

12. A method for manufacturing an anode, comprising: - Applying at least one composition T according to any one of claims 1 to 10 to a substrate; - Drying the coated substrate and then calendaring it. The manufacturing method.

13. - The application is carried out at a pH less than 7 or in the range of 4 to 6.5, or - The application of composition T to the substrate is carried out to the thickness after drying and calendaring on the metal surface, measured using a coating thickness gauge of 1 μm to 1,000 μm, i.e., less than 500 μm, preferably less than 100 μm or less than 50 μm, or - The application of composition T to the substrate is carried out to the thickness after drying and calendaring, measured using a coating thickness gauge of 1 μm to 1,000 μm, i.e., greater than 5 μm, or - The application of composition T to the substrate is uniform. The manufacturing method according to claim 12.

14. An anode produced according to the manufacturing method described in one of Claims 12 or 13.

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